Emmanuel Macron started his first full day as president-elect on Monday at the side of current French President Francois Hollande. Macron, who was Hollande's economy minister from 2014 to 2016, joined his former mentor at a ceremony commemorating the Allied victory over the Nazis in World War II.

The president-elect will officially take over from his former boss on Sunday as France's youngest-ever president.

The pro-European Union Macron vowed to "rebuild the relationship between Europe and the peoples that make it," after defeating his nationalist rival Marine Le Pen by a margin of 66.1 percent to 33.9 percent. On Monday, he said his first foreign visit would be to the EU's other great defender, German Chancellor Angela Merkel.

After his victory on Sunday night, Merkel praised the success of Macron and his independent, politically centrist En Marche! movement. The new French leader "carries the hopes of millions of French people and also many in Germany and across Europe."

'The vote was against Le Pen, not for Macron'

Although many across Europe were relieved that the anti-immigrant euroskeptic National Front (FN) leader Le Pen was defeated, many in France felt deflated after they felt they had chosen "the lesser of two evils," as one French voter put it to DW.

Indeed, a record number of voters, around 9 percent, cast a blank ballot, many  in protest to what they saw as a choice between a far-right extremist and a former investment banker turned Socialist, turned centrist with little political experience.

"This vote was in large majority against Marine Le Pen, and I think a lot of people who voted for Macron will go into the streets to protest against his policies, because this was not a vote for him but a vote against the other candidate," Ivanhoe Govoroff, a French journalist, told DW.

Govoroff's prediction soon came to pass. As the media across the world broadcast jubilation from Macron's victory celebration outside the Louvre museum in Paris, others joined the Monday's self-proclaimed "Social Front" marches through Paris to protest Macron's election.

The scant coverage from mostly French-language media estimated that the demonstrators calling for Macron's resignation numbered in the thousands. Although exact numbers were hard to come by, one thing was clear - the crowd of socialists, labor unionist and activists were worried that Macron's free-market policies will further hurt the already suffering French worker.

Le Pen too close for comfort

Many French voters also expressed their concern that despite the defeat, 34 percent of voters cast their ballot for Le Pen.

"We came very close to a National Front presidency," university student Fabien Camus told DW. "And we are seeing them become even stronger." Camus said that if Macron were able to bring down unemployment, he might be able to bridge the divisions facing the French in matters of economics and immigration.

While some world leaders such as British Prime Minister Theresa May, US President Donald Trump (though he had earlier backed Le Pen) and Chinese Premier Xi Jinping extended their congratulations to Macron almost immediately, one of the most interesting well wishes came on Monday morning from Russian President Vladimir Putin.

On Friday, a huge leak of documents from Macron's campaign appeared online. Although En Marche! insisted that real internal communications had been mixed in with fake ones to "create confusion," there were fear it could derail his campaign - similar to hacks on the Democratic National Convention and the emails of Hillary Clinton campaign chief John Podesta last year, which proved highly damaging to Clinton's chances.

Like the DNC and Podesta leaks, there have been allegations - though no proof - that the hackers are linked to the Russian government. The Kremlin has denied these claims, and on Monday published a statement to its official website saying President Putin hoped he and Macron could "overcome mutual mistrust and unite to ensure international stability and security."

While Macron did promise to combat international terrorism and climate change in his first public remarks as president-elect, his first big challenge lies at home. In June, two more rounds of voting will determine the make-up of France's 577-seat parliament. Macron will have to shore up support in the legislature if he hopes to have an easy time pursuing his policy agenda.

Additional reporting contributed by Erin Conroy.